Longitudinally adjustable surfboard fin with self-contained locking mechanism

ABSTRACT

SECURED WITHIN THE REARWARD UNDERSIDE SECTION OF A SURFBOARD IS A SURFBOARD FIN MOUNTING BOX WITH A CHANNEL AND A PAIR OF LONGITUDINALLY EXTENDING RUNNERS FORMED IN THEIR MARGINS WITH CUTAWAY ZONES THAT DEFINE A KEYWAY. A WEDGE-SHAPED BLOCK HAS TABS DEFINED A KEY SIZED TO FIT THROUGH THE KEYWAY. A FIN BASE HAS A SECTION THAT ALSO   HAS TABS DEFINING A KEY SIZED TO FIT THROUGH THE KEYWAY. A PUSH ARM COUPLED TO THE WEDGE-SHAPED BLOCK CAN BE MANUALLY OPERATED TO FORCE THE WEDGE-SHAPED BLOCK INTO TIGHT INTERLOCKING RELATIONSHIP WITH THE FIN BASE IN ORDER TO SECURELY POSITION A FIN ATTACHED TO THE FIN BASE.

June 22, 1971 R. K. JOHNSON 3,585,663

LONGITUDINALLY ADJUSTABLE SURFBOARD FIN WITH SELF-CONTAINED LOCKINGMECHANISM Filed Aug. 13, 1969 FIG. 2

INVIIN I ORY ROBERT KARL JOHNSON BY .PQJZZW 9 [2% ATTORNEYS UnitedStates Patent LONGITUDINALLY ADJUSTABLE SURFBOARD FIN WITHSELF-CONTAINED LOCKING MECHANISM Robert Karl Johnson, Ventura, Calif.,assignor to W.A.V.E. Corporation Filed Aug. 13, 1969, Ser. No. 849,738Int. Cl. A63c 15/00 US. Cl. 9310 10 Claims ABSTRACT OF THE DISCLOSURESecured within the rearward underside section of a surfboard is asurfboard fin mounting box with a channel and a pair of longitudinallyextending runners formed in their margins with cutaway zones that definea keyway. A wedge-shaped block has tabs defining a key sized to fitthrough the keyway. A fin base has a section that also has tabs defininga key sized to fit through the keyway. A push arm coupled to thewedged-shaped block can be manually operated to force the wedge-shapedblock into tight interlocking relationship with the fin base in order tosecurely position a fin attached to the fin base.

BACKGROUND OF THE INVENTION This invention relates to a surfboard finassembly and more specifically to a surfboard fin assembly that can bequickly and safely mounted within and shifted longitudinally along amounting box.

Conventional surfboards ordinarily have a skeg or fin rigidly fixed tothe rearward undersurface portion of the surfboard. While this typicalarrangement serves to perfectly align the fin and stabilize thesurfboard, the resulting unavoidable lack of versatility andremovability makes storage and handling of the surfboard and itsaccessories very cumbersome. Restriction to a single fin design alsominimizes the range of maneuvers that can be undertaken by the surfer.

In order to overcome the above mentioned disadvantages of fixed fins theconcept of an easily removable surfboard fin was developed as is fullydescribed in US. Pat. 3,422,471 to Morey et al. issued Jan. 21, 1969. Arelated approach for a demountable and interchangeable surfboard fin isdisclosed in copending US. application, Ser. No. 737,413 filed June 17,1968, now US. Pat. No. 3,516,099 and entitled Mounting Structure forRemovable Surfboard Fin.

A more advanced approach for increasing the versatility of demountableand interchangeable surfboard fins is disclosed in copending US.application, Ser. No. 811,810 filed Apr. 1, 1969, and entitled Sectionaland Longitudinally Adjustable Surfboard Fin Assembly. In essence thisstructure embodies a fin base section with tapered exterior side wallssized for wedging engagement against complementary tapered interior sidewalls of a mounting box. The fin base section can be selectivelyinterlocked with a fin section by employing a retaining plate that isslidably coupled to the fin base section and is located within anelongated channel formed by the fin base section. The retaining platehas a positioning groove for receiving a portion of the fin section.

Most surfboard fin assemblies constructed like those mentioned aboverequire the surfer to use a screwdriver, wrench or the like in order totighten the fin at a selected longitudinal location against the fin basesection or associated mounting box. If the surfer is compelled to storethe tightening tool in a remote location or inadvertently misplaces thetool then it becomes annoying when he wishes to adjust the longitudinalposition of the fin for undertaking a different surfing maneuver.

3,585,663 Patented June 22., 1971 ice As shall be fully described thelocking mechanism of this invention is totally incorporated within thesurfboard fin assembly itself and therefore the surfer is not botheredby the requirement to use external tools.

BRIEF SUMMARY OF THE INVENTION Briefly stated, this invention concerns asurfboard fin assembly that (1) can be easily assembled for use ordisplay and dismantled for storage or shipment, (2) embodies aself-contained locking mechanism so that external tools are notrequired, and, (3) is structured so that the fin section can be swiftlylocked in place and released for being repositioned.

The surfboard fin assembly has a fin mounting box installed within theundersurface of a surfboard. The mounting box has an elongated channeldefined in part by a pair of spaced longitudinally extending side wallsand a pair of inwardly extending elongated runners that are attached tothe mounting box side walls. A wedgeshaped block positionable in thechannel mounts a push arm that projects outwardly and downwardly fromthe mounting box so it can be easily grasped by a surfer and slidlongitudinally along the channel.

Structured to interlock with the wedge-shaped block is a fin base havinga pair of elongated flanges positioned to overlap and bear against theexterior runner walls. The fin base defines a ramp structure forreceiving and interlocking with the wedge-shaped block.

In order to stabilize the position of the fin base and thereby fix theposition of an associated fin, a surfer may grasp the push arm and slidethe wedge-shaped block progressively forward from a retracted position.As the wedge-shaped block enters and slides along the ramp structurewith a camming action, the fin base flanges are forced to bear tightlyagainst the mounting box runners to eventually firmly clamp the fin basein a desired position. To release the locking action the surfer merelymoves the push arm to a retracted position and, after the fin base hasbeen shifted to a different longitudinal position, he thrusts thewedge-shaped block forwardly into locking engagement again.

The wedge-shaped block has a longitudinally oriented slot extending fromone end that defines a pair of tapered prongs. The fin base has anintermediate narrow web, shaped to interfit with the slot and a pair oftapered guideways formed in part by the ramp structure which are shapedto receive the prongs.

Cut-out Zones on the inner margins of the runners constitute a keywaythrough which a first key defined by the wedge-shaped block and a secondkey defined by the fin base may pass in order to enter the fin mountingbox channel.

To facilitate alignment a series of sockets formed on the exteriorrunner walls may interfit with a series of corresponding pegs formed onthe fin base elongated flanges.

BRIEF DESCRIPTION OF THE DRAWINGS The numerous benefits and uniqueaspects of the present invention will be fully understood when thefollowing detailed description is studied in conjunction with thedrawings in which:

FIG. 1 is a perspective view partly broken away, showing thelongitudinally adjustable surfboard fin installed in the rearwardsection of a surfboard;

FIG. 2 is an exploded view showing the relationship between thewedge-shaped block and fin base components before they are mutuallyinterlocked; and,

FIG. 3 is a sectional view taken along line 33 of FIG. 2 showing thecross sectional shape of the push arm.

3 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 depicts aconventional surfboard with its rearward undersurface section 11 formedwith a rectangular cavity 12. Securely locked or bonded within cavity 11is a surfboard fin assembly 13 having a fin mounting box 14 with foreand aft sections :15 and 16 respectively. Box 14 has a longitudinallyextending elongated channel 17 formed in part by a pair of laterallyspaced side walls 18.

Extending inwardly towards one another from the mounting box side walls18 is a pair of elongated runners 19 and 20 formed with exterior wallsthat are exposed in FIG. 1 and interior walls that are concealed inFIG. 1. The forward section of runners 19 and 20 define a keyway .211constituted by a series of cut-out zones 22 in runner 19 and cut-outzones 23 in runner 20.

The inner margins of runners 19 and 20 are shaped with a series ofsockets 24 and 25 respectively which, as shall be fully explained, serveto assist in accurately longitudinally positioning components of thesurfboard fin assembly 13.

A first interlocking means constituted by a wedgeshaped block 26 isintegrally formed with or otherwise coupled to a push arm 27 thatdepends from the rearward portion of the Wedge-shaped block 26. Block 26coacts with a fin base 28 that incorporates a second interlocking meansin order to clamp the skeg or fin 29 in a desired position.

As clearly shown in FIG. 2 fin base 28 is integrally formed with a pairof elongated flanges 30 and 3-1 which, when fin base 28 is firmlysecured to fin mounting box 14, snugly fit against the exterior surfacesof runners 19 and 20 respectively. Fin base 28 has a ramp structure 32and a series of tabs 33 extending laterally from opposing sides of rampstructure 32. Tabs 33 constitute a key sized to fit through keyway 2-1shown in FIG. 1 in order to allow fin base 28 to become partiallyinserted within channel 17.

Pin base 28 has a vertically extending intermediate narrow web 34 which,along with ramp structure 32, define a pair of tapered guideways 35 and36 that converge in a rearward to forward direction.

The upper or concealed surfaces of changes 30 and 31 are formed with aseries of pegs 37 shaped to fit into and interlock with sockets 24 and25- in runners 19 and 20. For purposes of describing this aspect of theinvention only a few pegs 3-7 are shown together with a pair ofrearwardly disposed transverse pegs 38. The positions of the pegs andsockets could be interchanged.

Wedge-shaped block 26, which is shaped to tightly interfit with fin base28, includes a longitudinally oriented slot 39 extending rearwardly fromthe leading edge to an intermediate location. A pair of tapered prongs40 and 41, defined in part by slot 39, are shaped to straddle web 34 andfit into tapered guideways 35 and 36 respectively. A vertically alignedrib 42 is positioned to contribute strength to the rearward portion ofwedge-shaped block 26.

Extending laterally from prongs 40 and 41 are tabs 43 and 44respectively that, together, form a key structure. The eight tabs 40 and41 constituting the key structure of block 26 are sized to register withand fit through the eight cut-out zones 22 and 23 constituting thekeyway 21 of the fin mounting box 14.

The thickness of the upper fin base section and ramp structure 32 aswell as the thickness of wedge-shaped block 26 are dimensioned to beslightly smaller than the lateral distance across channel 17 As shall beexplained fully fin 29 can be adjustably positioned by shoving block 26from a retracted position in a direction indicated by arrow 45 into atight interlocking fit with fin base 28.

Referring now to FIG. 3 it can be seen that the forward wall portion ofpush arm "27 is characterized by a relatively large radius and that theside wall portions eventually converge to define a sharp angularrearward wall portion. The purpose of this configuration is to reducethe effects of drag and thereby promote streamlined movement of push arm27 as it travels in the wake of fin 29.

Operation Keeping the above construction in mind it can be understoodhow the previously stated disadvantages of conventional surfboard finassemblies are overcome or substantially eliminated by the presentinvention.

A surfer is able to haul the surfboard fin assembly 13 to a selectedsurfing area with the wedge-shaped block 26 and fin base 28 convenientlyand safely detached from one another as well as from the fin mountingbox 14.

To accurately and stably arrange the fin 29 for surfing maneuvers, thesurfer first installs the wedge-shaped block 26 into the channel 17 ofthe fin mounting box 14 by registering the tabs 43 and 44 of theassociated key structure with the cutout zones 22 and 23 of the keyway21. After the push arm 27 is manipulated to move the wed-geshaped block26 sufiiciently rearwardly then ramp structure 32 of the fin base 28 issimilarly inserted into the channel 17 by registering the tabs 33 of theassociated key structure with the cut-out zones 22 and 23 of the keyway21.

The surfer is now ready to tightly lock the fin 29 in a selectedlongitudinal position without resorting to external hardware ofimplements such as screwdrivers, wrenches or cranks, etc., and, withoututilizing any screws, bolts, nuts or other customarily employedfasteners.

Fin base 28 is held at a predetermined location against fin mounting box14 with pegs .38 inserted into corresponding sockets 24 and 25 in orderto facilitate alignment. Push arm 27 is then manipulated by a hand orsingle finger to progressively shove the wedge-shaped block 26 indirection 45 along ramp structure 32 and into interlocking relationshipwith the fin base 28. As the tapered prongs 40 and 41 are thrust deeperinto their corresponding tapered guideways 35 and 36 on opposing sidesof the intermediate narrow web 34 then they cam against the rampstructure 32 and force the base 28 deeper into the channel 17. Thiscoaction pulls the elongated fianges 30 and 31 against theircorresponding elongated runners 19 and 20 with ever-increasing forceuntil the desired interlock is completed. At this point in time thesurfer may release the push arm 27 and begin surfing.

In the highly unlikely event that block 26 and base 28 become loosenedfrom one another it would be virtually impossible for either to becomedetached from box 14 because the keys would be required to slip throughthe keyway 21. Rushing water during surfing would thrust them rearwardlyand away from keyway 21.

In order to adjust the fin position relative to the longitudinal axis ofthe surfboard 10 and fin mounting box 14 the surfer is merely requiredto break the locking force by retracting the push arm 27, shift the finbase 28- to the next selected position, and, manipulate the push arm 27to restore the locking force.

From the foregoing it will be evident that the present invention hasprovided a longitudinally adjustable surfboard fin assembly with aself-contained locking mechanism in which all of the various advantagesare fully realized.

What is claimed is:

1. A surfboard fin assembly comprising:

(a) a fin mounting box with an elongated channel defined in part by apair of spaced longitudinal extending side walls;

(b) first interlocking means insertable within the channel;

(c) a push arm coupled to the first interlocking means and shaped toproject outwardly from the mounting box so it can be grasped by aperson; and,

(cl) a fin base defining second interlocking means arranged to interlockwith the first interlocking means in response to selective manualoperation of the push arm.

2. The structure according to claim 1, wherein;

a pair of elongated runners extend inwardly towards one another from themounting box side walls, the runners having exterior and interior walls,

the first interlocking means is a wedge-shaped block,

the fin base includes a pair of elongated flanges arranged to overlapand seat against the runner exterior walls, and,

a ramp structure sized to receive and interfit with the wedge-shapedblock,

wherein, the push arm may be manually moved from a retracted position toslide the wedge-shaped block over the ramp structure to thereby causeclamping action between the fin base flanges and mounting box runnersand hold the fin base firmly in a desired position.

3. The structure according to claim 2, wherein the push arm is arrangedso that it is always aligned rearwardly of the fin base with respect tothe direction of intended forward movement by a surfboard.

4. The structure according to claim 2, wherein the push arm dependsgenerally perpendicularly relative to the fin mounting box plane, and,its cross section is shaped to reduce drag.

'5. The structure according to claim 2, including:

a longitudinally oriented slot extending from one wedge-shaped block endto an intermediate location; and

an intermediate narrow web defined by the fin base and sized to fit intothe slot to mutually orient the wedge-shaped block and fin base.

6. The structure according to claim 5, including:

a pair of tapered prongs defined in part by the slot; and

a pair of longitudinally tapered guideways formed in part by the rampstructure and intermediate narrow web, the guideways being sized toreceive and interfit with the prongs.

7. The structure according to claim 2, including:

a keyway defined by cut-out zones on the inner margins of the runners;

a first key defined by first tabs extending laterally from thewedge-shaped block; and

a second key defined by second tabs extending laterally from the finbase, the first and second keys being sized to fit sequentially throughthe keyway in order to admit the wedge-shaped block and fin base totheir relative positions within the mounting box channel.

8. The structure according to claim 2, including:

a series of sockets formed on the exterior runner walls;

and

a series of pegs formed on the fin base elongated flanges, the pegsbeing sized and spaced to interfit with corresponding sockets in orderto assist in clamping together the fin base and Wedge-shaped block.

9. A surfboard fin assembly with a self-contained locking mechanism,comprising:

'(a) a fin mounting box with an elongated channel defined in part by apair of spaced longitudinally extending side walls;

(b) a pair of elongated runners extending inwardly towards one anotherfrom the mounting box side walls, the runners having exterior andinterior walls;

(c) a keyway defined by cut-out zones on the inner margins of therunners;

(d) a wedge-shaped block insertable within the channel;

(e) a longitudinally oriented slot extending from one wedge-shaped blockend to an intermediate location;

(f) a pair of tapered prongs defined in part by the slot;

(g) a first key defined by first tabs extending laterally from thewedge-shaped block;

(h) a push arm coupled to the Wedge-shaped block and shaped to projectoutwardly from the mounting box so it can be grasped by a person;

(i) a fin base having a pair of elongated flanges arranged to overlapand seat against the runner exterior walls;

(j) a ramp structure sized to receive and interfit with the wedge-shapedblock;

('k) an intermediate narrow web defined by the fin base and sized to fitinto the wedge-shaped block slot to mutually orient the Wedge-shapedblock and fin base;

(1) a pair of longitudinally tapered guideways formed in part by theramp structure and intermediate narrow web, the guideways being sized toreceive and interfit with the prongs;

(m) a second key defined by second tabs extending laterally from the finbase, the first and second keys being sized to fit sequentially throughthe keyways in order to admit the wedge-shaped block and fin base totheir relative positions within the mounting box channel,

wherein the push arm may be manually moved from a retracted position toslide the tapered prongs over the ramp structure and into the taperedguideways to thereby cause clamping action between the fin base flangesand mounting box runners in order to hold the fin base firmly in adesired position.

10. The structure according to claim 9-, wherein:

the push arm is arranged so that it is always aligned rearwardly of thefin base with respect to the direction of the intended forward movementof a surfboard,

a series of sockets are formed on the exterior runner walls, and

a series of pegs are formed on the fin base elongated flanges, the pegsbeing sized and spaced to interfit with corresponding sockets in orderto assist in clamping together the fin base and wedge-shaped block.

References Cited UNITED STATES PATENTS 1/1969 Morey et al. 9310 6/1970Morey et a1. 9--310 US. Cl. X.R.

